1. Field of the Invention
The present invention is related to a method for configuring an Ethernet local area network to enable a talking device (e.g., microphone) to send a media stream to one or more listening devices (e.g., speakers).
2. Description of Related Art
Two standard committees are currently attempting to expand the use of Ethernet by enabling applications to be implemented on an Ethernet local area network (LAN) which require a high quality of service (low latency and low jitter) like a media stream application. The two standard committees are:                1. Audio/Video Bridging (AVB) Task Group (IEEE Std. 802.1Q™-2005)        2. Universal Plug and Play (UPnP) Forum        
The AVB task group is working on specifications that can be used to enable a media stream to be transported on an Ethernet LAN between a talking device and a listening device. While, the UPnP forum is working on specifications that will give the talking device and listening device enough information so they can set-up the media stream. In particular, the AVB task group is working on modifying the existing Ethernet technology which occasionally has latency and jitter on the order of tens of milliseconds that can make it difficult to transport a media stream over an Ethernet LAN between the talking device and the listening device. And, the UPnP forum is working on automating the task of configuring an Ethernet LAN so that the devices connected thereto like the talking device and the listening device can have enough information so they are able to set-up the media stream.
FIG. 1 (PRIOR ART) shows an example of the use of an AVB media stream 102 between a talking device 104 (e.g., microphone 104) which is the source of the media stream 102 and a listening device 106 (e.g., speaker 106) which is the destination of the media stream 102. In accordance with the existing AVB protocol, the speaker 106 needs to send a subscribe request 108 to the microphone 104 before it will be able to receive a high quality media stream 102 from the microphone 104. But, before this can happen, the microphone 104 needs to acquire a stream ID from an unspecified source and give that stream ID to the Ethernet LAN 100. And, the speaker 106 needs to obtain the same stream ID and the stream's bandwidth from an unspecified source. Then, once this is done, the speaker 106 can send the subscribe request 108 for the media stream by telling the Ethernet LAN 100 that it wants to subscribe to that stream ID. The AVB specification does not specify how the speaker 106 (listening device 106) learns the stream ID and the bandwidth of the media stream which outputs from the microphone 104 (talking device 104). This is done instead by UPnP which is, among other things, a “discovery protocol” that distributes information about end systems which are connected to an Ethernet LAN to other end systems which are also connected to the same LAN.
FIG. 2 (PRIOR ART) shows an example of the use of UPnP where the microphone 104 (talking device 104) and the speaker 106 (listening device 106) both advertise the information which will be used so they can set-up the media stream 102. As shown, the microphone 104 and the speaker 106 respectively broadcast advertisements 112 and 114 on the Ethernet LAN 100 indicating their presence and the services they provide. These advertisements 112 and 114 do not cause anything to happen, instead they just distribute information. This is all fine and well but there are still some technical problems related to the AVB and UPnP specifications which have not yet been solved by the two standards committees. These technical problems will be discussed in detail next with respect to FIGS. 3-8 (PRIOR ART).
FIGS. 3-5 (PRIOR ART) illustrate a large conference room 300 in an office building which is used to help explain some of the technical problems associated with the current AVB and UPnP specifications. The large conference room 300 has two microphones 104a and 104b and two speakers 106a and 106b all of which are connected to one another by a single Ethernet LAN 100 (not shown in this particular set of drawings). In FIG. 3, the large conference room 300 is divided into conference room A and conference room B by using a sliding partition 304. In this configuration, the first microphone 104a sends a media stream 102a to the first speaker 106a and the second microphone 104b sends a media stream 102b to the second speaker 106b. FIG. 4 shows the large conference room 300 with the partition 304 removed. In this configuration, one microphone 104a (for example) sends one media stream 102a to both speakers 106a and 106b. In both of these configurations, the AVB protocol is used to transport the necessary media streams 102a and 102b but it is the responsibility of the UPnP protocol to give the microphones 104a and 104b and the speakers 106a and 106b enough information so they can set-up the media streams 102a and 102b. FIG. 5 is a diagram showing the UPnP signaling and the AVB signaling between the first microphone 104a and the two speakers 106a and 106b which is needed to establish the media stream 102a utilized in the configuration shown in FIG. 4. In UPnP terminology, the microphones 104a and 104b are considered “control points” and the speakers 106a and 106b are considered “devices”.
The exemplary large conference room 300 shown in FIGS. 3-5 has three specific problems (which will be solved by the present invention). These problems are as follows:
1. The microphone 104a in conference room A should not have the option of talking to the speaker 106b in conference room B when the partition 304 is in place (see FIG. 6).
2. The speakers 106a and 106b (listening devices) do not in practice subscribe to microphones 104a and 104b (talking devices). Instead, the microphones 104a and 104b should subscribe to the speakers 106a and 106b (see FIG. 7).
3. The UPnP advertisements do not contain enough information such as positional information so one can properly configure the Ethernet LAN 100 (see FIG. 8).
FIG. 6 (PRIOR ART) is provided to illustrate the first problem in which the microphone 104a (located in conference room A) should not have the option of sending a media stream 102a to the speaker 106b (located in conference room B) when the partition 304 divides the large conference room 300. In other words, one does not want to get their virtual wires crossed between the microphone 104a (talking device) and the speaker 106b (listening device). The current AVB and UPnP specifications do not address this particular problem.
FIG. 7 (PRIOR ART) is provided to illustrate the second problem in which the speakers 106a and 106b (listening devices) are not the ones in practice that normally subscribe to microphones 104a and 104b (talking devices). In the current AVB specifications, the speaker 106 (listening device 106) needs to subscribe to a microphone 104 (talking device 104) but it's not likely that a speaker 106 is ever going to subscribe to a microphone 104. Because, the microphone 104 is most likely going to being used by a person and the speaker 106 is most likely going to be just hanging on a wall. In this case, it is the person that is using the microphone 104 who really needs to initiate the subscription. Thus, the AVB requirement where the listening device needs to subscribe to the talking device is not by itself practical in some “real-life” applications.
FIG. 8 (PRIOR ART) is provided to illustrate the third problem in which the current UPnP advertisements from the microphones 104a and 104b and the speakers 106a and 106b do not contain enough information so one can properly configure the Ethernet LAN 100. In particular, the speakers 106a and 106b advertise to every device on the Ethernet LAN 100 that they happen to be speakers 106a and 106b, but they don't say anything about where they happen to be located. Accordingly, there has been and is a need to address these shortcomings and other shortcomings which are associated with the current AVB and UPnP specifications. These needs and other needs are satisfied by the present invention.